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🛡️ CVE-2026-65981 on Ubuntu — coturn

⚪ Unknown ✅ No Known Exploit OSV
N/A
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

Coturn is a free open source implementation of TURN and STUN Server. Prior to 4.15.0, a server using --mobility authenticates a resumed REFRESH request with the resuming user's credentials but does not verify that identity against the original allocation owner, allowing an authenticated attacker who obtains a victim MOBILITY-TICKET to receive and inject relayed traffic and consume the victim's quota. In the handle_turn_refresh resume branch, the victim allocation (orig_ss) is located solely by the attacker-controlled mobile id, and credentials are only adopted (via copy_auth_parameters) when the resuming session is unauthenticated. Because the attacker's session already has hmackey_set set to 1 from its own prior authentication (which is never reset for long-term-credential sessions), the credential copy is skipped and check_stun_auth validates the REFRESH against the attacker's own identity rather than the allocation owner's. This issue is fixed in version 4.15.0.

Distribution advisory

This page covers CVE-2026-65981 as tracked by Ubuntu, for the package coturn. No fixed version has been recorded for this distribution yet.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is high, an attacker needs low-level privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality high, integrity high, availability low.

CVSS metrics in full

The score comes from this vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:L

  • Attack vector: Network — reachable from anywhere that can route to the service.
  • Attack complexity: High — the attacker first has to win a race, learn a secret or otherwise prepare the target.
  • Privileges required: Low — an ordinary user account is enough.
  • User interaction: None — nobody has to be tricked into anything.
  • Scope: Unchanged — the damage stays inside the vulnerable component.
  • Confidentiality impact: High — total loss, or loss the attacker controls.
  • Integrity impact: High — total loss, or loss the attacker controls.
  • Availability impact: Low — limited, and the attacker does not choose what is affected.

Weakness class

UBUNTU-CVE-2026-65981 is classified as CWE-639: Authorization Bypass Through User-Controlled Key. An object is selected by an identifier from the request without checking the caller owns it.

Affected software

UBUNTU-CVE-2026-65981 is recorded against 1 package.

  • coturn

Timeline and source

Published on 31 July 2026 and last revised on 6 August 2026. No public exploit is currently recorded for this entry. Record sourced from OSV.

References

ubuntu.com (Report)
www.cve.org (Report)
github.com (Report)
github.com (Report)

Other advisories for this package

coturn has other advisories on record. If you are patching this one, these are worth checking on the same host:

Same weakness in other software

These advisories are the same class of weakness (CWE-639: Authorization Bypass Through User-Controlled Key) in other software:

Details

Severity Unknown
CVSS Score N/A
CVSS Vector CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:L
CWE N/A
Public Exploit ✅ No
Source OSV
Published 2026-07-31
Updated 2026-08-20
Modified 2026-08-06
Fix URL N/A

Affected Packages

Software From version Fixed in
coturn — —

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ⓘ Data Notice: The information presented above has been compiled from publicly available internet sources. Boteraser aggregates this data solely for informational purposes and does not independently classify, evaluate, or endorse any findings about the vulnerabilities listed. The accuracy and completeness of this information is the sole responsibility of the original publishers. Boteraser and its operators accept no liability for any decisions made based on this data.

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